1. Field of the Invention
The present invention relates to a method and apparatus for straightening a bladed propeller that employs a pair of independently adjustable blade bending units, each preferably a hydraulically operated cylinder and pushrod device that enable pressure to be applied to a pair of spaced apart positions on a propeller, enabling either pitch and/or rake adjustments to be made to the propeller by simultaneously extending the spaced apart pushrods as they engage a selected one of the propeller blades.
2. General Background of the Invention
For many years, propellers have been manually straightened using a very large hammer with a plastic, polymeric or rubber head. Such hammers are commercially available from McDurmon Distributing of Fenton, Mich. Another example of such a hammer is sold by Garland Hammers (Garland Manufacturing Company) of Saco, Me.
Such a manual bending of a propeller in order to straighten it is both time consuming and imprecise. The present provides an improved method and apparatus for straightening propellers that enables precise bending of the propeller blades to achieve a desired change in rake and/or pitch.
Some propeller straightening devices have been patented. The following table lists examples of propeller repair patents.
TABLEPat. No.TitleIssue Date2,013,705Process for Shaping HelicalSep. 10, 1935Bodies and Means for Carryingout Said Process2,393,317Straightening Press forJan. 22, 1946Aircraft Propellers andthe Like3,032,092Propeller StraighteningMay 1, 1962Apparatus4,058,880Propeller Making ApparatusNov. 22, 1977and Method4,222,259Propeller ReconditionerSep. 17, 19805,315,856Apparatus for PropellerMay 31, 1994Straightening5,377,521Method for PropellerJan. 3, 1995Straightening5,713,233Vane Adjustment MachineFeb. 3, 1998